Fixes #6828: M428 bug

Marlin/Marlin_main.cpp

     bool err = false;
     LOOP_XYZ(i) {
       if (axis_homed[i]) {
-        float base = (current_position[i] > (soft_endstop_min[i] + soft_endstop_max[i]) * 0.5) ? base_home_pos((AxisEnum)i) : 0,
-              diff = current_position[i] - LOGICAL_POSITION(base, i);
+        const float base = (current_position[i] > (soft_endstop_min[i] + soft_endstop_max[i]) * 0.5) ? base_home_pos((AxisEnum)i) : 0,
+                    diff = base - RAW_POSITION(current_position[i], i);
         if (WITHIN(diff, -20, 20)) {
-          set_home_offset((AxisEnum)i, home_offset[i] - diff);
+          set_home_offset((AxisEnum)i, diff);
         }
         else {
           SERIAL_ERROR_START;